1. Field of the Invention
The present invention relates to a construction machine in which a boom of a working attachment is arranged to one of the left and right sides of a cab into which an operator gets on.
2. Description of the Related Art
In a hydraulic excavator, as shown in FIGS. 7 and 8, an upper rotating body 2 is disposed on a crawler type lower traveling body 1 rotatably around an axis O vertical to a ground, and a cab 4 serving as an operator chamber in which an operator gets on is provided on one of the left and right sides (hereinafter, a case where the cab is provided on the left side will be described) of an upper frame 3 of this upper rotating body 2. Further, a working attachment 6 provided with a boom 5 is attached to the right side of this cab 4 so as to be raised and lowered.
In FIG. 7, the reference numeral 7 denotes a counterweight provided at a rear end of the upper frame 3.
The cab standard (ROPS) regulates that at the time of rollover (tipover) of a machine main body, deformation of the cab 4 (sometimes called as displacement, shown by a long dashed double-short dashed line in FIG. 8) has to be suppressed so as to ensure operator space called as DLV (Deflection-Limiting Volume) in the cab against a lateral load W (refer to FIG. 8) imposed on the cab 4 toward the boom 5 (the right side).
In order to comply with this ROPS standard, as shown in Patent Documents 1 and 2, there is a configuration in which a load transmission member is provided on a side surface or the like of the boom 5, and the lateral weight W from the cab 4 is transmitted to a load receiving member (the boom 5, or an exclusive member attached to the boom 5 or the like) via this load transmission member.    [Patent Document 1] Japanese Patent Laid-Open No. 2008-105669    [Patent Document 2] Japanese Patent Laid-Open No. 2008-291541
In this case, the lateral load is transmitted to the load receiving member as soon as the cab 4 is brought into contact with the load transmission member, that is, contact between the cab 4 and the load receiving member becomes just earlier by the load transmission member. Therefore, energy of the load itself cannot be reduced.
Thus, although movement of the cab 4 toward the boom can be suppressed, the deformation of the cab 4 is still not sufficiently suppressed.